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11 Biology
Chapter 10, Unit 4
Term | Definition |
---|---|
macromolecule | a very large molecule made up of smaller molecules that are linked together |
metabolism | the sum total of all the chemical reactions that occur in an organism |
essential nutrient | a nutrient that cannot be made by the body, and must therefore be obtained from food |
monosaccharide | a simple sugar with three to seven carbon atoms |
disaccharide | a sugar made up of two monosaccharide molecules |
polysaccharide | a large molecule made up of many linked monosaccharide molecules |
glycogen | a polysaccharide made up of glucose units |
lipid | an organic compound that does not dissolve in water, such as fat and oil |
amino acid | a building block of protein |
peptide bond | a bond that holds together the amino acids in a protein |
polypeptide | a linear chain of several amino acids linked by peptide bonds |
hydrolysis | a chemical reaction in which water breaks apart macromolecules into smaller molecules |
enzyme | a protein molecule that helps speed up important chemical reactions in the body |
alimentary canal | the tube through which food is processed, beginning at the mouth and ending at the anus; also know as the digestive tract |
mechanical digestion | the physical breakdown of large pieces of food into smaller pieces in the mouth by the actions of teeth, beak, or other similar structures, and churning motions in the stomach |
chemical digestion | the chemical breakdown of nutrient molecules into smaller molecules by enzyme action |
salivary glands | glands in the mouth that produce saliva to begin the chemical digestion of food |
saliva | a watery secretion in the mouth that begins the digestive process |
esophagus | the muscular tube through which food passes from the mouth to the stomach |
peristalsis | a wave-like series of muscular contractions in the esophagus |
gastric juice | a mixture of hydrochloric acid, salts, enzymes, water, and mucus that is produced by the glands in the stomach to help digest food |
chyme | a thick liquid produced in the stomach and made of digested food combined with gastric juice |
pepsin | an enzyme in gastric juice that helps break down proteins into polypeptides |
duodenum | a short, wide U-shaped section of the small intestine into which food passes from the stomach |
villi | finger-like projections lining the surface of the small intestine that increase the surface area to improve the absorption of nutrients |
jejunum | the portion of the small intestine that follows immediately after the duodenum |
ileum | the portion of the small intestine that follows immediately after the jejunum |
bile | a greenish-yellow fluid secreted by the liver that helps digest fat |
peptic ulcer | a sore in the lining of the stomach or duodenum, most commonly caused by infection with the bacterium Helicobacter pylori |
inflammatory bowel disease | the general name for a group of diseases that cause inflammation in the intestines |
Crohn's disease | a form of inflammatory disease that can affect any part of the alimentary canal from the mouth to the anus |
ulcerative colitis | a form of inflammatory disease that attacks the colon |
hepatitis | inflammation of the liver, most commonly cause by a virus |
cirrhosis | the irreversible replacement of healthy liver tissue with non-functioning scar tissure; most commonly caused by excessive alcohol intake or hepatitis |
diabetes | a condition in which the body is unable to use glucose for energy |